I downloaded .net4.5 as a standalone install and that worked. I then rebooted. I then tried to install drivepool 2.0 and got:
[15D0:15D4][2021-08-10T15:08:40]i011: Launched elevated engine process.
[15D0:15D4][2021-08-10T15:08:40]i012: Connected to elevated engine.
[15F8:15FC][2021-08-10T15:08:40]i358: Pausing automatic updates.
[15F8:15FC][2021-08-10T15:08:40]i359: Paused automatic updates.
[15F8:15FC][2021-08-10T15:08:40]i360: Creating a system restore point.
[15F8:15FC][2021-08-10T15:08:40]i362: System restore disabled, system restore point not created.
[15F8:15FC][2021-08-10T15:08:40]i370: Session begin, registration key: SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{446ce5b3-377f-48e0-8565-5f187d90e240}, options: 0x7, disable resume: No
[15F8:15FC][2021-08-10T15:08:40]i000: Caching bundle from: 'C:\Users\ADMINI~1\AppData\Local\Temp\2\{4A9C4B07-B47C-4660-8931-EFDD0C9E4DB8}\.be\StableBit.DrivePool_x64.exe' to: 'C:\ProgramData\Package Cache\{446ce5b3-377f-48e0-8565-5f187d90e240}\StableBit.DrivePool_x64.exe'
[15F8:15FC][2021-08-10T15:08:40]i320: Registering bundle dependency provider: {446ce5b3-377f-48e0-8565-5f187d90e240}, version: 2.2.1237.0
[15F8:15FC][2021-08-10T15:08:40]i371: Updating session, registration key: SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{446ce5b3-377f-48e0-8565-5f187d90e240}, resume: Active, restart initiated: No, disable resume: No
[15F8:162C][2021-08-10T15:08:40]i304: Verified existing payload: DrivePoolApplication at path: C:\ProgramData\Package Cache\{43053F4F-87D0-4459-A600-03896AC6F486}v2.2.1237\StableBit.DrivePool.msi.
[15F8:15FC][2021-08-10T15:08:40]i323: Registering package dependency provider: {43053F4F-87D0-4459-A600-03896AC6F486}, version: 2.2.1237, package: DrivePoolApplication
[15F8:15FC][2021-08-10T15:08:40]i301: Applying execute package: DrivePoolApplication, action: Install, path: C:\ProgramData\Package Cache\{43053F4F-87D0-4459-A600-03896AC6F486}v2.2.1237\StableBit.DrivePool.msi, arguments: ' ARPSYSTEMCOMPONENT="1" MSIFASTINSTALL="7" LAUNCHUI="1" INSTALLLOCATION="C:\Program Files\StableBit\DrivePool"'
[15F8:15FC][2021-08-10T15:08:45]e000: Error 0x80070643: Failed to install MSI package.
[15F8:15FC][2021-08-10T15:08:45]e000: Error 0x80070643: Failed to execute MSI package.
[15D0:15D4][2021-08-10T15:08:45]e000: Error 0x80070643: Failed to configure per-machine MSI package.
[15D0:15D4][2021-08-10T15:08:45]i319: Applied execute package: DrivePoolApplication, result: 0x80070643, restart: None
[15D0:15D4][2021-08-10T15:08:45]e000: Error 0x80070643: Failed to execute MSI package.
[15F8:15FC][2021-08-10T15:08:45]i318: Skipped rollback of package: DrivePoolApplication, action: Uninstall, already: Absent
[15D0:15D4][2021-08-10T15:08:45]i319: Applied rollback package: DrivePoolApplication, result: 0x0, restart: None
[15F8:15FC][2021-08-10T15:08:45]i329: Removed package dependency provider: {43053F4F-87D0-4459-A600-03896AC6F486}, package: DrivePoolApplication
[15F8:15FC][2021-08-10T15:08:45]i372: Session end, registration key: SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{446ce5b3-377f-48e0-8565-5f187d90e240}, resume: None, restart: None, disable resume: No
[15F8:15FC][2021-08-10T15:08:45]i330: Removed bundle dependency provider: {446ce5b3-377f-48e0-8565-5f187d90e240}
[15F8:15FC][2021-08-10T15:08:45]i352: Removing cached bundle: {446ce5b3-377f-48e0-8565-5f187d90e240}, from path: C:\ProgramData\Package Cache\{446ce5b3-377f-48e0-8565-5f187d90e240}\
[15F8:15FC][2021-08-10T15:08:45]i371: Updating session, registration key: SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{446ce5b3-377f-48e0-8565-5f187d90e240}, resume: None, restart initiated: No, disable resume: No
[15D0:15D4][2021-08-10T15:08:45]i399: Apply complete, result: 0x80070643, restart: None, ba requested restart: No
So back to square 1. Should I uninstall everything, or maybe reformat my disks and re-install WHS2011 from the original DVD again?